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Most motors exhibit positional torque ripple known as cogging torque. In high-speed motors, this effect is usually negligible, as the frequency at which it occurs is too high to significantly affect system performance; direct-drive units will suffer more from this phenomenon unless additional inertia is added (i.e. by a flywheel) or the system ...
Direct torque control (DTC) is one method used in variable-frequency drives to control the torque (and thus finally the speed) of three-phase AC electric motors.This involves calculating an estimate of the motor's magnetic flux and torque based on the measured voltage and current of the motor.
Torque motors can be used as actuators for direct-drive mechanisms in some situations where otherwise geared electric motors would be used: for example, in motion control systems or servomechanisms. Actuators are hardware devices that converts the controller command signal into a change in a physical parameters.
A motor with windings in delta configuration gives low torque at low speed but can give higher top speed. Wye configuration gives high torque at low speed, but not as high top speed. [dubious – discuss] The wye winding is normally more efficient. Delta-connected windings can allow high-frequency parasitic electrical currents to circulate ...
The motor speed varies as a non-linear function of load torque and armature current; current is common to both the stator and rotor yielding current squared (I^2) behavior [citation needed]. A series motor has very high starting torque and is commonly used for starting high inertia loads, such as trains, elevators or hoists. [2]
The direct drive, high torque motor design made it suitable for push-button cueing for selecting tracks on radio broadcasts and in dance clubs. Besides these features, it also had pitch control , which allowed the user to change the turning speed of the record (also BPM: beats per minute ) gradually from -8% to +8%.
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Direct-current motors with series field windings are the oldest type of traction motors. These provide a speed-torque characteristic useful for propulsion, providing high torque at lower speeds for the acceleration of the vehicle, and declining torque as speed increases.